The present invention relates to new D-allose derivatives, and more particularly, to new D-allose type nitrosourea derivatives and a process for the preparation thereof as well as a new antitumor agent containing the derivative as an active ingredient.
Various nitrosourea derivatives have been synthesized by many researchers and it has been reported that these derivatives exhibit antitumor effects.
It is known that nitrosourea derivatives, such as 1-(2-chloroethyl)-2-(methylcyclohexyl)-1-nitrosourea (Me-CCNU), 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU) and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), are effective against early stage encephalophyma, melanoma, lymphoma, etc.
Further, various compounds, such as streptozotocin (J. Amer. Chem. Soc., 89, 4808 (1967)), chlorozotocin (J. Med. Chem., 18 (1), 104 (1975)) and glycopyranoside amine derivatives (Jap. Pat. Laid-Open No. 144319/1979), are known as sugar nitrosourea derivatives, and it has been reported that they exhibit antitumor effects.
However, in order for a certain compound to be effective as an excellent antitumor agent, the compound should act specifically and selectively on tumor cells with a minimal effect on normal cells.
The inventors have perfected the present invention upon conducting intensive investigations made for the purpose of obtaining compounds which are extremely safe and which exhibit excellent antitumor effects.